The Americans called it a ‘suicide’ attack and put the number of injured at seven. Later, they gave the age of the girl as between 16 and 18.

The attack illustrates the lengths to which some militants are prepared to go, especially as Islam forbids women taking part in war.

However, such religious sensitivities mean women are less likely to stopped and searched at checkpoints.

There have also been reports of bombings involving mental patients and people in wheelchairs. In February, two women with Down’s syndrome were used as human bombs in Baghdad. They walked among the crowds before the devices were detonated with mobile phones, killing 99 people.

Joe Stork, from Human Rights Watch, said militants used such bombers because security forces were cracking down on traditional tactics.

‘In the Palestinian conflict it was not something that happened at the outset – it was later on. You could infer as bombings became more and more difficult for the usual suspects to pull off they resorted to children.’

The attack came on the day that Metro revealed that 100,000 girls being used as soldiers around the world.

Elsewhere in Iraq, a suicide bomber killed 20 mourners at a funeral attended by Sunni tribesmen opposed to al-Qaeda.

In Baghdad, a car bomb detonated next to an MP’s convoy. He survived, but a civilian was killed and 20 others were wounded.